1. Field of the Invention
The present invention relates to an apparatus of forming semiconductor devices, and more particularly, to a chamber in which an observation device is installed so as to observe and inspect a wafer and a processing state.
2. Description of Related Art
The semiconductor devices, such as a LSI (Large Scale Integrated), a memory IC (Integrated Circuit) and other logic elements, are generally fabricated by repeated depositing and patterning processes. Fabricating the semiconductor devices widely includes epitaxy process, thin film deposition process, diffusion/ion-injection process, photolithography, etching process, and so on. Among these fabrication processes, the thin film deposition process and the etching process are prerequisite for the semiconductor devices. Especially, these deposition and etching processes are performed in a processing chamber module having airtight reaction rooms.
The processing chamber module has variable configurations and structures depending on a process of designation. When the etching and patterning processes are required for the thin film deposited on the wafer, a plasma etcher (often referred to as a plasma processing chamber module) is utilized.
FIG. 1 schematically illustrates a processing chamber module diagram according to a conventional art. The processing chamber module 10 includes a chamber 20 which is airtight and inside which a thin film is formed, etched, patterned and so on. The processing chamber module 10 also includes a storage 40 that contains source materials and chemical reactants for supplying them into the chamber 20 during the designated process.
Inside the chamber 20, a wafer 1 is mounted on a chuck 30 (e.g., an electrostatic chuck). The chamber 20 includes an inflow pipe 23 through which the source materials and chemical reactants contained in the storage 40 is supplied, and an outflow pipe 24 through which residual gases are exhausted to control the pressure of the chamber 20. An insulating plate 26 is located in an upper part of the chamber 20 and divides the chamber 20 into a first region 28a and a second region 28b. In the first region 28a, a plasma generator 50 is installed to produce the plasma in the second region 28b. The chuck 30 on which the wafer 1 is laid is located in the second region 28b. 
When the source materials and chemical reactants are streamed into the chamber 20 from the storage 40 via the inflow pipe 23, the plasma generator 50 generates an electromagnetic field and makes plasma in the second region 28b. Therefore, the thin film formed on the wafer 1 is etched and patterned using the plasma. Connected to the chuck 30 is a power source 60 for supplying power to attract the wafer 1 to the chuck 30 and for applying a bias voltage to the chuck 30.
When processing the semiconductor devices in the above-mentioned processing chamber module 10, the inside of the chamber 20 is isolated from the outside in order to obtain a stable processing progress. Also, the processing parameters in the chamber 20, such as pressure and temperature, are controlled different from the outside atmosphere. Namely, the inside surroundings of the chamber 20 has a distinguishable reaction system differentiating from the outside. For this reason, the chamber 20 is usually made of a metallic material including stainless steel that is relatively cheaper. However, since the metallic material for the chamber 20 is opaque, it is impossible to observe and inspect the wafer processes. This phenomenon is not limited only in the plasma processing chamber module for etching and patterning. If such a process chamber module made of an opaque metallic material is used in other processes, e.g., deposition process and cleaning process, non-observation and non-inspection are definitely expected during the processing of wafer.
Moreover, during the process for the semiconductor devices, a high air-purity is essential throughout the manufacturing field in order to protect the semiconductor devices from impurity contamination. To obtain the high purity, the personnel of the factory and the staffs are controlled and restricted to enter the manufacturing field. Therefore, it is quite difficult to detect the process errors and the malfunction of the processing apparatuses.
Especially in these days, the most semiconductor companies established an unmanned factory with a completely automated apparatus system in order to prevent the contamination caused by the personnel or staffs and to increase the productivity of the semiconductor devices. Thus, if a wafer misalignment, a wafer deformity caused by a temperature variation, a wafer mis-transfer, and the process malfunction in the chamber occur during the process, these faults may be repeated because they are not detected early in the process. Further, these faults result in the loss of materials and the waste of cost.